Sine protractor



P 9, 5 R. A. MULL 2,609,612

SINE PROTRACTOR Filed Aug. 14, 1946 v 2 SHEETS-SHEE'i 1 E fg f3) Jn"if};

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R. A. MULL SINE PROTRACTOR Sept. 9, 1952 2 SHEETSSHEET 2' Filed Aug. 14,1946 illl Patented Sept. 9, 1 952 Raymond Arthur Mull, St; JosephTownship,

Berrien County, Mich.

.n pii ationnugusi 14, 1946, SerialNo. 690,371

This invention relates to improvements insine protractors, and more,especially to a novel sine protractor structure wherein a sine bar ispivotally mounted upon a readily portable base.

An important object of the present invention is to provide a new andimproved sine protractor in which any desired angular setting can bequickly and easily obtained merely by blocking up one end of the sinebar member of the protractor.

Another object of the inventionis to provide a sine protractor of thistype in which the preferred setting is adapted to be maintainedpositively in a manner to permit the protrac'tor .to be moved from placeto place in use without disturbing the angular setting or requiring anyresetting of the device for the predetermined angle for which theprotractor has been adjusted.

A further object of the invention is to provide a hinged sine protractorhaving improved means for maintaining the same in any selected'pos'itionof angular adjustment.

Still another object of the invention is to .provide a hinged sineprotractor having improved resilient means for maintaining the sameinangular adjustment.

It is also an object of the invention'to provide in a sine protractorimproved means for maintaining a gage block in assembled position topermit handling of the device in adjusted condition for movement tovarious points of use.

A still further object is to providea sine protractor which is readilyadapted to serve as a support for work pieces to be machined to one aparticular angle.

Yet another object of the invention is toprovide a sine protractor whichis readily portable in set or adjusted condition and is adapted to bereversed at will for presenting a supported work piece in reversedangularit'y to a tool or machine to work thereon or 'for'checkingreverse angles, etc.

Other objects, features, and advantages ofthe present invention will be'readily'apparent from the following detailed description of certainpreferred or exemplary embodiments of the invention and in theaccompanying 'two sheets of drawings wherein:

Figure 1 is a top .plan view of a sine protract'or *4 Claims. (Cl.33174) embodying therieat'ures o'f'the present invention;

Figure 2 is a side elevational viewofthe sine protractor; l

Figure 3 isa vertical detail sectional view taken substantiallyintheplane of line III-"III of'tFigure 2; g

Figure 4 is a side levational view of the sine protractor, showing thesame adjusted to a desired working angle, and, with certain parts brokenaway and .in' section to reveal details of structure;

Figurefi is an isometric view of a gage'blc'ck holder adapted to -beusedwith the sine -protra'ctcr;

Figure-6 is a side .elevational'v'iew of a slightly .modifiedvform ofthe sine protractor; I Figure 7 is .a fragmentary longitudinal sectionalview through a (further modified form-of the invention; and I Figure 8is a fragmentary "longitudinalsectional detail View of aifurthermodifiedj-form of thein vention.

A sine .protractor according tothe pr'esent inventionis adapted to beconstructed in the form of a small compact-{unit comprising a 'sineioarI-0 and a base bar 'H of approximately-the same length and preferably ofthe same width hingedly connected together at one end by'me'ans of 'ahinge .pin 12. For this purpose the base-bar H maybe formed at .itshinge end with al -spaced parallel integral pair "of upstanding ears I 3providing there'between aparallel wall'slot or groove '14 within whichis'r'e'ceived ahinge tongue 15integral with the compa'nionend of thesinebar l 6. An accurately machined sliding bearing fit is provided between.thefhin'ge' ears and tongue" for accurac-yin operation. 7 I

The top .face vo'f the 'sine bar'i'fi and the bottom face of the basebar'l'i are both machined to a high degree of flat planar accuracy, "andthe .hinge axis through the .pinll2 is disposed in a line with theparallel axis of .a gaging cylinder [1 adjacent to the opposite end ofthe sine bar 1'0. In the closed position of {the .protractor, as shownin Fig. 2, said line between the hinge and cylinder axes is parallel -tothe top and-bottom faces of the device. 1 w I 'In order Ito accommodatea gage blocker-gage 5o blockassemblytlt upon-the upperv-face=of the basebar II and thereby enable the gage blocks to be carried along with theprotractor when it is moved from place to place, the gaging cylinder I!is carried by the lower or inner face of the sine bar It and mayconveniently be mounted within a gage block clearance recess iii in thesine bar under-face. A cradling forward corner formation 20 receives thecylinder 11 and provides a seat or base therefor. By preference, thecylinder base 20 is formed on a complementary radius to afford maximumbearing engagement of the cylinder therewith.

Means such as a screw 2i extending through a rearwardly diagonal bore 22in the forward end of the sine bar it and opening radially through thecylinder base 20 is threaded into a screw socket 23 formed radially inthe cylinder 11.

The head of the screw 2| engages an outwardly screw head sunk below theupper face bf me sine bar.

The diameter of the gaging cylinder the thickness of the base bar I IWhere the cylinder contacts it or the gage blocks l8 are mounted are sorelated that the two bars extend in true parallelism in the fullycollapsedcondition of the protractor.

The distance between the axes of the hinge pin I2 and the cylinder 11 ispredetermined, preferably according to usual sine bar practice, to fiveinches or ten inches, as desired. Therefore any angle desired in the topsurface of the sine bar It can be attained by referenceoto a table ofnatural since and setting or adjusting the angle of sine bar l so thatthe perpendicular distance between the gaging cylinder I1 and the topsurface of the base bar II is the proper multiple, that is five ortimes, as the case may be, of the natural sine of the angle to beachieved. In other words, the base bar I l herein serves as the surfaceplate for the sine bar H) with one end of the sine bar at all times infixed pivotal relation to the surface plate.

The gage blocks iii are of the customary type used for setting sinebars, and means are preferably provided on the base bar H for retainingthe gage blocks removably in place and against accidentally beingdislodged when the protractor is moved from place to place in use.This-enables the protractor to be set'for any preferred angle and thenmoved to wherever it is needed. This afiords a great convenience forinspection purposes and for tool or work set-up purposes. To this end, aretainer 25 is provided which may be in the form of a fiat plate adaptedto rest fiatwise against the upper gage block supporting surface of thebase bar It and is equipped with ll, and" a retaining slot 2'! (Fig. 5)of a width to receive the lower end or the edge of the gage block 28closely. By preference, the retainer 25 is or substantial length so thatthe slot 2'! can be made long enough to receive the gage blocklengthwise on edge as well as on end.

The retainer plate 25 is adapted to be held in place on the base bar Hby means such as integral retainer pins or dowels 28 extended slidablyinto appropriate sockets 29 in the base late. be readily lifted up torelease the dowels 28 from the sockets 29 for removing the'gage blocksby sliding them off the base bar. Likewise, in efiecting an adjustmentassembly the retainer In this way, the retainer plate 25 can plate 25can be put in place after a selected gage block has been slid onto thebase bar.

Another feature which is" valuable in maintaining a particular angularsetting of the sine protractor provides a means for holding the sine barI0 and the base bar II in substantially clamped relationship withrespect to the gage blocks I8. This means may comprise a contractilespring member 30 engaged at one end upon the stem of a handle 3|projecting from the free end of the sine bar 10 and at the other endupon the stem of a handle 32 extending from the free end of the base barll. As the sine bar It is swung open or away from the base bar H thespring 30 is placed under tension and thereby acts to hold the sine bartight against the top of the gage block 18. If preferred, of course, theclamping spring 30 may be disconnected from either or both of thehandles 31 or 32 until the desired angular adjustment of the sine barill has been effected and then the spring can be stretched and anchoredonto the handle or handles from which it has been disconnected.

In another form (Fig. 7), an expansile compression spring structure 33may be provided to act between the rearwardly protruding ends orextensions of sine bar Wu and base bar Ha beyondthe hinge I2a.- For thispurpose, the end extensions may have therein respective opposing sockets-34'f'or' retaining the ends of the compression spring. With thisarrangement when the sine bar we is swung up, the end extensionsof thebars with the compression spring 33 therebetween. swing toward oneanother and place the spring under compression. The com pression load ofthe spring 33 reacts to urge the opposite or gaged end portions of thebars toward one another into compressing relation to the gagerblock l8assembly therebetween.

In addition to the compression spring 32, or as an alternativetherefore, the sine protractor may be equipped with a contractiletension spring 35 operative inwardly from the hinge l2a. This may be inthe form of a coil spring having integral opposite terminal hooks 3!engaging respective transverse anchoring pins 38 within sockets 39 and40 formed in alignment in the opposing inner faces of the sine bar Illaand the base bar Ha, respectively. With this spring 35, as the bars arespread apart in eifecting an adjustment, the spring is expanded andplaced under tension thereby reacting to draw the bars toward oneanother.

Where it is preferred or necessary to effect positive locking of thebars in adjusted condition, the structure shown in the modification ofFig. 8 may be adopted. In this form, the sine bar 10b and the base bar[lb have end extensions beyond the outer side of the hinge I2b similarto the end extensions shown in Fig. 7. This affords an opposing 'jawstructure. A knurlheaded, micrometer-threaded locking screw 4! isthreaded through the end extension of the sine bar and bears against theopposing face of the end extension of the base bar. This locking screwis adapted to be driven home after the desired angular adjustment of thebars has been eiiected and acts to urge the bars to pivot about thehinge 12b to drive them toward one another and thereby into tightclamping engagement against the gage block assembly utilized ineffecting the angular adjustment. If desired, of course.

the locking screw, 41 may comprise a click asgages expedients of theforms oflFigures '7 and 8, the tension spring at maybeusedg'orpputtingit the other wamen one or a combination of the expedients' shown inFigures'7 and'8 may beiused with the tension spring"3'9'." 'On the otherhand anyof thelc'cking or holding e'xpedients may be used alone.Furthermore; instead of compression or tension springs as shown in theform of Fig. '7, an obviously equivalent torsion spring structure may besubstituted or used as a supplement. 7

While in the form of the hinge shown in Figures l to 4, inclusive, thehinge pin I2 and the cylinder ll are of' the same-diameterfor purposesof economy and expediency as well asto conform to the usual practice, atleast in the visual sense, the really important thing is to have theaxes of the hinge pin and the gaging cylinder in a common plane parallelto the effective surfaces of the bars in the fully collapsed position ofthe device. As seen in Fig. 6, the sine bar we and the base bar Ilc arehingedly connected by a hinge pin 42 of substantially greater diameterthan the gaging cylinder [70. However, the axis of the hinge pin 42 isin a common plane with the axis of the gaging cylinder Ho and such planeis strictly parallel to the top or angle face of the sine bar I00. Onthe other hand, the hinge pin could be substantially smaller in diameterthan the gage cylinder, but the larger size hinge pin as well as thehinge pin bearings in the bars are easier to machine to the requisiteaccuracy.

As an aid in locating work, with respect to a cutting or shaping tool,such as a milling cutter, for example, while utilizing the sineprotractor as a support for the work upon which an angular face orsurface is to be machined the upper or angle determining face of thesine bar It is preferably equipped with work-stop means such as a pin43. This pin 43 is preferably removably and adjustably received in oneor more pin sockets 44 sunk within the upper angle surface of the sinebar. As shown, by way of example, a longitudinal series of the pinsockets 44 is provided, herein three in number and located in theportion of the sine bar nearest the hinge. By having the stop pin 43removable, it can be readily mounted in any one of the sockets 44 or itcan be removed entirely where the angle face of the sine bar is to beleft free.

By having the sine and base bars relatively narrow the protractor can beused in working environments of relatively small lateral clearance, andparticularly where the protractor is to be used as a work support in amachine in which work is to be done upon the supported Work piece.

Another advantage inherent in the present sine protractor is that it canbe readily utilized for measuring, determining, or inspecting, for reverse angles or for supporting a work piece for machining of reverselyangular surfaces. This is adapted to be effected merely by turning theprotractor about end for end, without any need for readjusting since theprotractor when adjusted retains such adjustment as a complete working,self-contained unit. Of course, should it be necessary to change theangular adjustment for operational reasons at any time, as for examplewhen the protractor serves as a work piece support in machining, thiscan be accomplished quite expeditiously, merely by separating the sinebar ID from the gage block assembly l8 and adjusting the gage blockassembly to the calculated height and returning or allowing the sine barto return to the gaged relationship to the gage block or block assembly.

It will thus-"be observed-that I have not only provided a sine:protractorof unusual simplicity and efficiency but one which extremelyversatile with respect to the typeof'work-to which it can be applied,and which "is quite adaptable, largely b cause of its capability ofquick adjustinentf nd ready adaptability for uses requiring it tobemoved from place-toplace while in a predeterminedistate of angularadjustments.

It"v willrof course, be understood that various details cfconstructionmaybe varied through a wide range without departing from the principlesof this invention and his, therefore, not the purpose to limit thepatent granted hereon otherwise than necessitated by the scope of theap-' pende'd'claims. r

I claim as my invention:

1. In a sine protractor structure, a gage block retainer comprising aplate having a longitudinal retainer slot dimensioned to affordsuificient clearance to receive a gage block therein for seating againsta plane surface of a protractor member, and retaining pins on said plateextending from a face thereof adjacent to the opposite ends of saidslot. 7

2. In combination in a sine protractor, a portable base member, asinebar member having one end portion pivotally connected to one end portionof said base member, said members being ceiving surface, a sine barmember cooperatively related to the base bar member for angulardisposition relative to said plane surface, a fiat retainer frame lyingon said plane surface and having a slot therein of a width and length toreceive a gage block either lengthwise or on end closely between thelongitudinal edges defining the slot and with the gage block restingaccurately in face to face relation on said plane surface, and means forretaining said retainer frame against displacement in any directionparallel to said plane surface.

4. In combination in a sine protractor, a base bar, a sine bar, meanspivotally connecting said bars adjacent to one end, said sine bar havingon the inner side of the opposite end portion thereof gaging meansopposing the inner surface of the base bar, a gage block retainercomprising a frame having an opening for receiving a gage block thereinwith sufiicient clearance to seat therethrough, and means on saidretainer for removably connecting the retainer to said base bar on theinner face'area thereof opposing said gaging means of the sine bar,whereby a gage block can rest against the inner face of the base barthrough said opening insaid retainer and Will be held by the retaineragainst sliding off of r the base bar when the protractor is transportedfrom place to place with a gage block set-up therein.

RAYMOND ARTHUR MULL.

(References on following page) REFERENCES CITED Number The followingreferences. are of record in the 2317226 file of this patentz' r: STATESPATENTS 5 2:397:3oO Number Name ,7 Date 2,398,121 500,046, Ahne June20,1893 2,409,817 910,330 Wait Jan. 19, 1903 2,429,517 1,395,664 BensonNov. 1, 1921 1,409,343 Karasick Mar. 14, 1922 10 1,532,910 McCann Apr.'1, 1925 Number 1,766,546 Robs June 24, 1930 365,244 1,816,464 BiggertJuly 28, 1931 2,075,008 Damm Mar. 30, 1937 2,111,299 Robbins Mar. 15,1938 15 2,147,800 Sadowski' Feb. 21, 1939 2,296,820

Lester Sept. 22, 1942 8 Name Date Seyferth Apr. 20, 1943 Lovenston June20, 1944 Wisne June 19,1945 Tilton Mar. 26, 1946, Silvermaster Apr.9,1946 Webber Oct. 22, 1946 Knapp Oct. 21, 1947 FOREIGN PATENTS CountryDate France Sept. 5, 1906 OTHER REFERENCES American Machinist, page 540,Aug. 16, 1933. Johansson Cat. #17, Ford Motor 00., Dearborn, Mich., page23. Reod Aug. 9, 1945.

